So, who uses mainframes? Just about everyone has used a mainframe computer at one point or another. If you ever used an automated teller machine (ATM) to interact with your bank account, you used a mainframe.

Today, mainframe computers play a central role in the daily operations of most of the world's largest corporations. While other forms of computing are used extensively in business in various capacities, the mainframe occupies a coveted place in today's e-business environment. In banking, finance, health care, insurance, utilities, government, and a multitude of other public and private enterprises, the mainframe computer continues to be the foundation of modern business.

Until the mid-1990s, mainframes provided the only acceptable means of handling the data processing requirements of a large business. These requirements were then (and are often now) based on running large and complex programs, such as payroll and general ledger processing.

The mainframe owes much of its popularity and longevity to its inherent reliability and stability, a result of careful and steady technological advances that have been made since the introduction of the System/360™ in 1964. No other computer architecture can claim as much continuous, evolutionary improvement, while maintaining compatibility with previous releases.

Because of these design strengths, the mainframe is often used by IT organizations to host the most important, mission-critical applications. These applications typically include customer order processing, financial transactions, production and inventory control, payroll, as well as many other types of work.

One common impression of a mainframe's user interface is the 80x24-character "green screen" terminal, named for the old cathode ray tube (CRT) monitors from years ago that glowed green. In reality, mainframe interfaces today look much the same as those for personal computers or UNIX® systems. When a business application is accessed through a Web browser, there is often a mainframe computer performing crucial functions behind the scenes.

Many of today's busiest Web sites store their production databases on a mainframe host. New mainframe hardware and software products are ideal for Web transactions because they are designed to allow huge numbers of users and applications to rapidly and simultaneously access the same data without interfering with each other. This security, scalability, and reliability is critical to the efficient and secure operation of contemporary information processing.

Corporations use mainframes for applications that depend on scalability and reliability. For example, a banking institution could use a mainframe to host the database of its customer accounts, for which transactions can be submitted from any of thousands of ATM locations worldwide.

Businesses today rely on the mainframe to:

• Perform large-scale transaction processing (thousands of transactions per second)
• Support thousands of users and application programs concurrently accessing numerous resources
• Manage terabytes of information in databases
• Handle large-bandwidth communication

The roads of the information superhighway often lead to a mainframe.